Circuit breakers are one of a variety of overcurrent protection devices used for circuit protection and isolation. The circuit breaker provides electrical protection whenever an electric abnormality occurs. In a circuit breaker, current enters the system from a power line and passes through a line conductor to a stationary contact fixed on the line conductor, then to a movable contact. The movable contact can be fixedly attached to a pivoting arm. As long as the stationary and movable contacts are in physical contact, current passes from the stationary contact to the movable contact and out of the circuit breaker to down line electrical devices.
In the event of an overcurrent condition (e.g., a short circuit), extremely high electromagnetic forces can be generated. The electromagnetic forces repel the movable contact away from the stationary contact. As shown by an example of a prior art circuit breaker in FIG. 1, the circuit breaker 10 includes a stationary contact 30, a moveable arm 35, and a mechanism assembly 10m with a cam assembly 100 that includes a “C” that communicates with a cam follower 50. Because the movable contact 35c is fixedly attached to the rotating arm 35, the arm 35 pivots and physically separates the stationary 30 and movable contacts 35c, thus tripping the circuit. Upon separation of the contacts and blowing open the circuit, an arcing condition occurs. The breaker's trip unit will trip the breaker which will cause the contacts to separate.
FIGS. 2A and 2B illustrate an example of the mechanism assembly 10m with the cam assembly 100. Conventionally, the cam assembly 100 holds the components on the shaft 101 via rivets.